The disclosed device relates to transmissions for motorized vehicles. More particularly it relates to a device which functions as a transmission which is coupled at an input end to power sources such as an internal combustion or turbine engine and transmits the energy from that power source to drive wheels or prop or other propulsion component of a vehicle varying the amount of torque and speed delivered the engine to fit the immediate requirements of the vehicle. The disclosed device could additionally function as a brake for vehicles when configured differently by attaching the output shaft to a generator or other device doing work, or to a fixed position on the frame of the vehicle, and the input shaft to the drive shaft or other shaft that communicates with the wheels of the vehicle to be slowed.
Engine driven vehicles such as automobiles, buses, tractors, boats, and similar vehicles, conventionally use a transmission to communicate power and torque developed by the engine, to the wheels or drive of the vehicle. Additionally, helicopters and boats are frequently in need of changing the nature of the power transmitted from the engine to the propulsion components powering them varying both the torque and speed to a varying requirement. Early vehicles and current industrial vehicles frequently use a manual transmission which contains a series of different gears which may be interrelated to take input power from the engine and output that power to the wheels with sufficient torque and speed for the vehicle while maintaining the engine at optimum speed to operate.
Automatic transmissions operate to provide the same communication of variable torque and speed to the rear wheels only they do not require manual manipulation by the user nor a clutch to disengage the transmission during gear changes. Just like that of a manual transmission, the automatic transmission""s primary job is to allow the engine to operate in its narrow range of speeds while providing a wide range of output speeds and torque to the drive wheels with which it communicates engine power. Without a transmission, vehicles would therefor be limited to one gear ratio and that ratio would have to be selected to allow the car to travel at the desired top speed. Such an arrangement would provide a vehicle with little acceleration when starting out, and, at high speeds, the engine would be nearing it maximum revolutions.
The key difference between a manual and an automatic transmission is that the manual transmission locks and unlocks different sets of gears to the output shaft to achieve the various gear ratios, while in an automatic transmission the same set of gears produces all of the different gear ratios. The planetary gearset in the automatic is the device that makes this possible in an automatic transmission. However, planetary gearsets, bands that lock parts of a gearset, and wet clutches that lock other parts of the gear set are prone to failure and slippage. Further, and incredibly complicated hydraulic control system is required to control the clutches and bands and gear sets of a conventional automatic transmission lending more potential problems to long term reliability in such devices.
As such, there is a pressing need for a transmission which will automatically vary the amount of torque and speed communicated to the wheels of a vehicle from the engine. Such a transmission should have few moving parts and systems to help insure reliability and ease of maintenance. Such a device should provide the optimum torque and speed to the wheels from the engine while allowing the engine to rotate and operate at its optimum performance speed.
The above problems and others are overcome by the herein disclosed constant velocity transmission which provides maximum torque and speed from the engine to the output shaft and the communicating drive component such as wheels on a vehicle, while maintaining the engine at optimum operational speed. The device herein disclosed and described features a minimum of moving parts and control systems to enhance reliability and performance over conventional automatic transmissions which as noted require a plethora of parts and complicated hydraulic operating and control systems.
The herein disclosed and described constant velocity transmission takes advantage of the principle of fluid friction to transmit rotational forces providing torque and speed to the output shaft from rotating input shaft communicating with the drive motor. Rotating freely or inside of an appropriate housing, the device develops fluid friction between the major components thereby communicating power from the input shaft, connected to the driving motor to an output shaft which rotates in direct correlation to the motor speed. This fluid friction transfers energy communicated from the rotating motor to the output shaft by way of the fluid friction that develops in the layers of fluid moving in the housing in relation to the input shaft velocity. Initially fluid friction is substantially zero until vanes about the circumference of the inside rotating cone shaped drive cone, laterally translate upon the sloped outer surface of the drive cone and move outward toward the inner ribbed surface of the outer drum. As they move closer to inside surface of the outer drive drum, the vanes increase the fluid friction on the inner ribbed surface thereby exerting more pressure on the outer drum and moving it in the direction of rotation. This fluid friction increases proportionally as the vanes move closer to the driven drum and decreases proportionally as the vanes laterally translate on the drive cone and move away from the driven drum.
This device will function using any number of different viscosity fluids for fluid friction communication, from conventional transmission oil to water with near equal efficiency since the determining factor is the distance between the translating vanes and the inner surface of the driven drum. In the case of watercraft, the water in which the boat itself moves might be used as the fluid for the device and provide additional benefits from an in exhaustive source and inherent cooling from such a large reservoir.
This device features a front input shaft communicating power from the drive engine to a drive cone, supported on the input shaft inside of a driven drum which in turn communicates power to an output shaft via the aforementioned fluid friction. The input shaft is appropriately supported by bearings and communicates this support to the drive cone. The driven drum acts as a housing for the components which serve to operate the assembled device and is filled with a working fluid such as hydraulic oil.
The drive cone which is housed internally in the driven drum has slidable drive vanes along its circumference which laterally translate about the center axis of the drive cone. This lateral translation of the drive vanes on the slope or incline of the drive cone frustro-conical shaped exterior causes the distal edges of the drive vanes to move closer to or further away from the vaned interior surface of the driven drum. As the translating drive vanes move outward closer to the inside vaned surface of the driven drum, the working fluid builds up fluid friction between the different layers of fluid moving at different velocities. This fluid friction rotates the output drum with a force that is in relation to the distance between the drive cone mounted vanes and the stater vanes formed on the surface of the drive strum. The smaller the distance, the greater the fluid friction and the consequential greater applied torque. Conversely, the greater the distance, the less applied torque.
The operation of the device herein disclosed and described is dependent on a working fluid, in this case, light weight oil such as conventional transmission oil. While some of the fluid remains internal inside the driven drum assembly, in the current best mode a reservoir of additional working fluid is stored in an external reservoir until the input shaft is rotated by an external power source such as a conventional gasoline or diesel engine. The input shaft has splines similar in shape to those of a hydraulic pump rotor and rotate inside a pump housing thereby providing pump operation as the shaft rotates. This pumping action provides the means to pressurize the operating fluid of the device during use.
The input shaft which communicates rotational power from the attached motor, supported by conventional bearings appropriately positioned in the outer housing supports the driven drum. The input shaft terminates into a bearing at the rear of the driven drum at an end plate which is attached to the output shaft which communicates power from the motor to the wheels or other device being powered. This arrangement thus allows the input shaft to rotate the drive cone located inside the driven drum, independently of the driven drum assembly with the communicating motor driving the input shaft and the driven drum driving the output shaft. Fluid friction transfers rotational energy from the drive cone and translating vanes thereon to the driven drum. The fluid friction intensity is inversely proportional to the distance between the movable drive vanes and the driven drum stator vanes. The smaller this distance, the larger the fluid friction.
Lateral translation of the vanes along the center axis of the drive cone about the slanted exterior surface is provided by a controllable pressure actuator plate. The pressure actuator plate acts to press upon the rear surface of the vanes and translate them up the ramps on the frustro-conical drive cone. A biasing means such as a spring acts on one end of the pressure actuator to move it rearward while a second controllable biasing means such a hydraulic pressure acts on the other end of the pressure actuator to move it toward the drive cone. By increasing the pressure acting to move the pressure actuator toward the drive cone, the reverse pressure from the rearward biasing means is overcome. Conversely, by decreasing the pressure of the second controllable biasing means, the bias provided by the rearward biasing means overcomes that of the controllable biasing means thereby moving the controllable pressure actuator plate away from the drive cone and allowing the vans to translate to a lower position on the drive cone and further away from the stator vanes of the driven drum. In this fashion, the torque from the input shaft communicated to the output shaft from the driven drum may be easily and accurately controlled to an infinite number of settings rendering the device infinitely variable in its ability to adjust the torque communicated to the output shaft.
As noted above, the device as herein described and disclosed could not only provide an infinitely variable transmission for a vehicle, but also a means to brake the speed of the vehicle by hooking the device to communicate with the rotating wheels on one end, and a fixed position on the vehicle or to a generator or pump on the output end to brake the vehicle by doing work.
Accordingly, it is the object of this invention claimed herein to provide a simplified automatic transmission device to transmit power from a power plant at varying amounts of torque and speed to the component being driven by the power plant.
It is another object of this invention to supply an automatic transmission for a vehicle to transmit power from the engine to the wheels at optimum levels of torque for the moment while concurrently maintaining engine speed at optimum levels.
It is still another object of this invention to supply a device which can also function as a brake for a vehicle by providing resistance to the rotation supplied from the output shaft to the device.
Further objectives of this invention will be brought out in the following part of the specification, wherein detailed description is for the purpose of fully disclosing the invention without placing limitations thereon.